The rapid spread of West Nile virus has emphasized the role mosquitoes play as vectors for microbes and[unreadable] viruses that cause human infectious diseases. Some of these diseases such as malaria, dengue fever,[unreadable] yellow fever and various forms of viral encephalitis affect millions of people each year and are of great[unreadable] public health concern. A multi-component strategy is necessary to effectively combat and control these[unreadable] diseases. A important component of this strategy is the control of mosquito populations. Our long term goal[unreadable] is to understand the transcriptional mechanisms that control mosquito metamorphosis. This molecular[unreadable] information will be used to model and test more effective, and specific, mosquito control agents. In addition,[unreadable] this information will be used in the construction of transgenic mosquitoes that will reduce wild populations of[unreadable] adult female mosquitoes, and in protocols that drive specific genetically engineered genes into indigenous[unreadable] mosquito populations. This proposal concerns the expression of genes that may play a central role in[unreadable] mosquito metamorphosis. The conserved transcription factor gene AaHR3 is expressed early during[unreadable] mosquito metamorphosis and may play a central role in this process. Application of the juvenile hormone[unreadable] analogue methoprene to larvae causes lethality by interfering with metamorphosis. Methoprene also[unreadable] interferes with AaHR3 expression during metamorphosis. The coincidence of these effects suggest that[unreadable] methoprene interferes with mosquito metamorphosis by inhibiting induction of transcription factor AaHR3.[unreadable] In vitro culture of larval midguts will be used to determine if methoprene directly, or indirectly interferes with[unreadable] the expression of this transcription factor gene during ecdysone induced metamorphic midgut remodeling.[unreadable] In addition RNA interference (RNAi) will be used to determine if induction of AaHR3 controls mosquito[unreadable] metamorphosis. AaHR3 specific RNAi will be injected into larvae, or will be ingested by larvae. The effect of[unreadable] this RNAi will be assayed microscopically and biochemically by in situ hybridization and real time PCR. The[unreadable] role of other transcription factor genes, such as Aa75b, AaBetaFTZ-F1 and Broad complex, in midgut[unreadable] metamorphosis will also be investigated by the technique of RNA interference.